Combined pressurizing and relief valve for fire extinguishers

ABSTRACT

A combined pressurizing and relief valve in the control head of a fire extinguisher including a spring-biased valve member controlling flow between the external fill port and the pressure vessel of the extinguisher and between the fill port and venting openings. The valve member is provided with a small piston area in communication with the pressure vessel for operating the valve to allow excessive pressure within the vessel to flow out through the fill port. The valve member is also provided with a large piston area in communication with the fill port for operating the valve first to allow charging fluid entering the fill port to flow to the pressure vessel and, when the vessel is properly pressurized, to further operate the valve to allow the charging fluid to flow out through the venting openings.

D United States Patent 1 1 3,580,274

[72] Invent r Arn Hansel! 458,891 9/1891 Fisher 137/102 New York, NY. 2,989,971 6/1961 Valentine 137/ 102 5; i ppd 32 3,2 2 3,002,520 10/1961 Morse 137/102 1e [45] Patented May 25, 1971 901 061 7 F T 137 493 [73] Assignee Walter Kidde& Company, Inc. Great ritain Belleville, NJ. Primary Examiner-M. Cary Nelson Assistant Examiner-R. B. Rothman AttorneyDarby & Darby [54] COMBINED PRESSURIZING AND RELIEF VALVE FOR FIRE EXTINGUISHERS 3 Chums 1 Drawing ABSTRACT: A combined pressurizing and relief valve in the [52] US. Clcontrol head of a fire extinguisher including a spring-biased l37/509 valve member controlling flow between the external fill port [5 l ll lt. Cl F16k 17/18 and the pressure vessel of the extinguisher and between the fill [50] Fleld 0f Search 1 37/493, rt and venting openings The valve member is provided with 469, 509 a small piston area in communication with the pressure vessel References Cited for operating the valve to allow excessive pressure within the vessel to flow out through the fill port. The valve member is UNrTED STATES PATENTS also provided with a large piston area in communication with 1,221,719 4/ 1917 Fritch 137/469 the fill port for operating the valve first to allow charging fluid 1,495,491 5/1924 LeCain..... 137/493 entering the fill port to flow to the pressure vessel and, when 2,364,812 12/ 1944 Pierson 137/469 the vessel is properly pressurized, to further operate the valve 3,425,444 2/1969 Jones 137/469X to allow the charging fluid to flow out through the venting 3,460,567 10/1967 Martin 137/596 openings.

Patented May 25, 1971 VENTOR A E HANSEN GENT COMBINED PRESSURIZING AND RELIEF VALVE FOR FIRE EXTINGUISHERS BACKGROUND OF THE INVENTION The present invention relates to valves, and more particularly to pressurizing valves and pressure relief valves for apparatus for confining and dispensing fluid medium under pressure such as fire extinguishers, insecticide sprayers and the like.

In apparatus of the class described, it has been common practice to provide separate pressurizing and relief valves in the control head of the apparatus. Each valve and other sealing point represents a potential leakage point and therefore it is desirable to eliminate as many of these sealing points as possible. 7

Apparatus of this type is conventionally pressurized from a fluid source which is at a much higher pressure than that desired within the pressure vessel of the apparatus. The conventional pressurizing valve is either mechanically operated (e.g. of the type used in automobile tires) or is of the simple check type valve type. Therefore, it has been necessary in the past to exercise care to prevent over pressurization.

SUMMARY Accordingly, an object of the present invention is to provide in apparatus of the class described, a single valve which functions both as a pressurizing valve and as a relief valve.

Another object is to provide such a valve which prevents the apparatus from being over pressurized.

In accordance with the present invention the foregoing objects are generally accomplished by providing a combined pressurizing and relief valve in a body adapted to be mounted on a pressure vessel comprising in combination means providing a chamber within the body, means providing a first fluid passageway extending from one end of the chamber to be in communication with the pressure vessel, means providing a second fluid passageway extending from the chamber to fill port in the body, means providing a venting passageway from the other end of the chamber to the atmosphere, a springbiased valve member in the chamber moveable between a lower position wherein the other passageways are sealed from each other, an intermediate position wherein the first and second passageways are in communication, and an upper position wherein the second passageway is also in communication with the venting passageway, the valve member having a first piston surface in communication with the first passageway and a second piston surface in communication with the second passageway for moving the valve member from its first position into its second or third position in response to the pres sure within the pressure vessel and the pressure in the second passageway.

A preferred embodiment of the invention has been chosen for purposes of illustration and description, and is shown in the accompanying drawings, forming a part of the specification, wherein:

The single FIGURE of the drawing is a fragmentary longitudinal sectional view of a fire extinguisher control head embodying a valve according to the present invention.

Referring now to the drawing in detail, there is shown a section of a fire extinguisher control head 10 incorporating a valve according to the present invention. The control head 10 has an upper section 11 and a cylindrical base section 12 positioned in the neck 14 of a pressure vessel 15 in which the extinguishing agent is stored under pressure.

In accordance with standard practice, the control head contains a discharge control valve disposed within a flow path interconnecting a discharge outlet and a syphon tube extending into the pressure vessel. The discharge control valve and the flow path which it controls are positioned in the part of the control head which has been cut away and since they do not form a part of the present invention they are not shown or described herein.

Referring again to the drawing, the upper section 11 of the control head is provided with a vertically extending stepped bore 16 forming a valve chamber 17. The bore 16 includes an upper large diameter threaded portion 19, a lower cylindrical portion 20 of smaller diameter, and an intermediate conical portion 21 joining the portions 19 and 20. A threaded cap 22 is threaded into the bore portion 19. A bore 24 extends from the lower end of the chamber 17 downwardly through the base section 12 to form a passageway between the interior of the pressure vessel 15 and the chamber 17. A pressurizing fitting 25 is provided on the exterior surface of the upper control head section 11, and a horizontal bore 26 provides a passageway between the port 25 and the chamber 17. A plurality of apertures 27 are provided in the cap 22 to place the upper end of the chamber 17 in communication with the atmosphere.

A valve member 30 is positioned in the chamber 17 and includes a small diameter lower end section 31 dimensioned to fit within the bore 24, an upper section 32 dimensioned to fit within the bore portion 20, and a central section 34 having an intermediate diameter. The lower end section 31 is provided with an annular groove 35 in which an O-ring sealing member 36 is positioned to provide a fluid seal between the section 31 and the bore 24. Likewise, the upper section 32 is provided with an annular groove 37 in which an O-ring seal 39 is positioned to seal the section 32 to the bore 20.

The end of the section 31 presents a piston surface 40 to the pressure within the pressure vessel 14, and the sections 32 and 34 present piston surfaces 41 and 42 to the pressure within the lower end of the chamber 17. The section 31 is of sufficient length to maintain the surface 40 within the bore 24 throughout all stages of operation of the valve. A vertical bore 44 extends downwardly into the valve member 30, and a spring 45 is seated in the bore and bears against the cap 22 to bias the valve member downwardly. A conical surface 46 is provided at the junction of the bores 24 and 20, to guide the sealing member 36 into the bore 24. The section 31 is further provided with a pair of intersecting diametrical bores 47 and a longitudinal bore 49 extending upwardly from the surface 40 to intersect the bores 47.

In operation, the pressure vessel is pressurized by connecting the fitting 25 to a source of gas under pressure. The gas flows through the bore 26 into the lower portion of the chamber 17 and acts upon the surfaces 41 and 42 to lift the valve member 30 against the force of the spring 45. The pressure of the gas source is sufficient to force the valve member 30 upwardly to a position where the seal 36 has moved out of the bore 24 and and the bores 47 are adjacent the conical surface 46. The pressurizing gas then flows into the pressure vessel through the bores 47, 49, and 24.

As the pressure builds up within the vessel 15 it acts upon the surface 40 of the section 31 to cause further upward motion of the valve member 30. The spring 45 is designed so that when the pressure vessel 15 approaches the desired pressure, the upper seal 39 is adjacent to the lower edge of the conical surface 21. Further pressurization moves the seal 39 out of contact with the bore 20, and flow through the bore 26 then vents to the atmosphere through the apertures 27 preventing over pressurization of the vessel 15.

The source of gas is then disconnected from the fitting 27, and the pressure within the chamber 17 vents to the atmosphere through the bore as the spring 45 forces the valve member 30 back into the position shown in the drawing.

Should the pressure within the vessel 15 subsequently increase substantially, for example, as a result of being exposed to abnormal temperatures, the increased pressure acting against the surface 40 forces the valve member 30 upwardly placing the bore 24 in communication with the lower end of the chamber 17 to permit the excess pressure to vent through the bore 26 to the atmosphere.

It will be seen from the foregoing, that the present invention provides in apparatus of the type described a single valve which functions both as a pressurizing valve which prevents the apparatus from being over pressurized and as a relief valve.

As various changes may be made in the form, construction and arrangement of the parts herein, without departing from the spirit and scope of the invention and without sacrificing any of its advantages, it is to be understood that all matter herein is to be interpreted as illustrative and not in any limiting sense.

lclaim:

l. A combined pressurizing and relief'valve for a pressurized container, said valve including a body mounted to said pressurized container, said body formed with a chamber, means forming an inlet passage to said body in fluid flow communication with said chamber through which said container is to be pressurized from a source of pressurized fluid, said body also being formed with a first passage in fluid flow communi cation between the interior of said container and said chamber, and a vent passage in fluid flow communication between said chamber and the atmosphere surrounding said body, a valve member located in said chamber movable between a closed position blocking fluid flow communication between said inlet passage and said first passage and an open position for permitting fluid flow between said inlet and said first passages, spring means biasing said valve member into said closed position, said valve member having a first piston area in fluid flow communication with said inlet passage to move said valve member against the biasing force of said spring to said open position upon application of the pressurizing fluid from the source to said inlet passage, said valve member also having a second piston area in fluid flow communication with the interior of said container to move said valve member to said open position in response to excessive pressure within said container in the absence of the pressurizing fluid being applied to the inlet passage, said first and second piston areas also moving said valve to a position to provide fluid flow communication between the inlet passage and the vent passage in response to a combined excess pressure in the container on said second piston area and the pressure on said first piston area from the pressurizing fluid.

2. A valve as in claim 1 wherein said valve member is of stepped construction having a large diameter shoulder at an intermediate portion thereof forming said first piston area and having a small diameter end section located in a portion of said first passage which comprises said second piston area.

3. A valve as in claim 2 wherein said chamber of said body includes a bore having a stepped construction, the portion of said valve member defining said first piston area located in the larger diameter portion of the bore and the portion of the valve defining said second piston area located in the smaller diameter portion of the bore. 

1. A combined pressurizing and relief valve for a pressurized container, said valve including a body mounted to said pressurized container, said body formed with a chamber, means forming an inlet passage to said body in fluid flow communication with said chamber through which said container is to be pressurized from a source of pressurized fluid, said body also being formed with a first passage in fluid flow communication between the interior of said container and said chamber, and a vent passage in fluid flow communication between said chamber and the atmosphere surrounding said body, a valve member located in said chamber movable between a closed position blocking fluid flow communication between said inlet passage and said first passage and an open position for permitting fluid flow between said inlet and said first passages, spring means biasing said valve member into said closed position, said valve member having a first piston area in fluid flow communication with said inlet passage to move said valve member against the biasing force of said spring to said open position upon application of the pressurizing fluid from the source to said inlet passage, said valve member also having a second piston area in fluid flow communication with the interior of said container to move said valve member to said open position in response to excessive pressure within said container in the absence of the pressurizing fluid being applied to the inlet passage, said first and second piston areas also moving said valve to a position to provide fluid flow communication between the inlet passage and the vent passage in response to a combined excess pressure in the container on said second piston area and the pressure on said first piston area from the pressurizing fluid.
 2. A valve as in claim 1 wherein said valve member is of stepped construction having a large diameter shoulder at an intermediate portion thereof forming said first piston area and having a small diameter end section located in a portion of said first passage which comprises said second piston area.
 3. A valve as in claim 2 wherein sAid chamber of said body includes a bore having a stepped construction, the portion of said valve member defining said first piston area located in the larger diameter portion of the bore and the portion of the valve defining said second piston area located in the smaller diameter portion of the bore. 